Lubrication system and oil cooler with bypass

ABSTRACT

An oil cooler for an engine or other lubricated mechanism includes a connector through which the oil cooler is connected to an oil supply passage and a return oil passage in an engine crankcase or other supply source. The connector includes a seal face to which inlet and outlet passages from the cooler are connected with oil supply and return passages in a connected mechanism. A continually open oil bypass is provided by forming a groove or slot in the seal face of the oil cooler extending between the inlet and outlet passages of the oil cooler and forming the cooler oil bypass. Alternatively, a bypass may be formed by a slot in a mating engine or mechanism connector connecting with the supply and return oil passages. Using a perimeter gasket between mating connectors can increase the bypass oil flow by the area of the clearance within the gasket opening created by the thickness of the gasket.

TECHNICAL FIELD

This invention relates to a lubrication system for a lubricatedmechanism, such as an engine, transmission or other mechanism includingan oil cooler and a bypass for the oil cooler.

BACKGROUND OF THE INVENTION

It is known in the art, relating to engines, transmissions and othermechanisms, to provide an oil cooler for maintaining the oil temperaturebelow a desired maximum operating limit. The cooler may have a core witha plurality of oil passages in heat exchange relation with coolantpassages adapted to carry cooling fluids such as water or air.

In operation, oil degradation or deposits, as well as high oil viscositywhen the oil is cold, may impede oil flow through the cooler oilpassages. To avoid inadequate lubrication of the mechanism, a coolerbypass may be provided to maintain oil flow to the mechanism componentsuntil the oil warms to normal operating temperature, or the cooler oilflow is restored by changing the oil or servicing or replacing the oilcooler. Devices such as a pressure actuated bypass valve or a simpleorifice may be provided for this purpose. However, such arrangements mayadd cost or complexity to a lubrication system.

SUMMARY OF THE INVENTION

The present invention provides a lubrication system with an oil coolerfor an engine or other lubricated mechanism. The oil cooler includes aconnector through which the oil cooler is connected to an oil supplypassage and a return oil passage in an engine crankcase or other supplysource. The connector includes a seal face to which inlet and outletpassages to and from a cooler core are connected with oil supply andreturn passages in an engine or other connected mechanism. A continuallyopen oil bypass is provided by forming a groove or slot in the seal faceof the oil cooler connector, the slot extending between the inlet andoutlet passages of the oil cooler and forming the cooler oil bypass.Alternatively, a bypass may be formed by a slot in a mating engine ormechanism connector, connecting with the engine oil supply and returnoil passages.

These and other features and advantages of the invention will be morefully understood from the following description of certain specificembodiments of the invention taken together with the accompanyingdrawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of part of an engine lubrication systemhaving an oil cooler with a cooler bypass according to the invention;

FIG. 2 is a side view of an oil cooler adapted for attachment to anautomotive engine or other lubricated mechanism;

FIG. 3 is a face view of a connector for inlet and outlet passages toand from the oil cooler core and including a bypass slot extendingbetween the passages;

FIG. 4 is a view similar to FIG. 3 showing an alternative mating engineconnector with an oil cooler bypass slot;

FIG. 5 is a view similar to FIG. 3 including a perimeter gasket inposition for attachment of the oil cooler connector to a mating engineconnector; and

FIG. 6 is a diagrammatic cross-sectional view through the oil coolerconnecter along the line 6-6 of FIG. 5 showing the bypass flow areathrough the slot and between the assembled flanges of an oil coolerattached to an engine.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Referring now to the drawings in detail, numeral 10 generally indicatespart of a lubrication system for a lubricated mechanism, such as anengine 12, a transmission or other mechanism, not shown. Engine 12includes a suitable housing such as a cylinder block or crankcase 14with an oil sump or oil pan 16 for containing a supply of lubricatingoil. Within the crankcase or oil pan, an engine driven oil pump, notshown, is provided for supplying pressurized oil from the oil pan 16 tothe various internal moving components of the engine 12.

The lubrication system includes an oil cooler 18 having a housing 20which may be mounted at any convenient location, such as on a side 22 ofthe cylinder block or crankcase 14. An exemplary form of oil cooler 18with housing 20 is illustrated in FIG. 2. The oil cooler is provided tocool the engine oil as needed to maintain a desired temperature below amaximum operating temperature level. The oil cooler housing 20 mayinclude a core 24 having a plurality of cooling oil passages 26extending between inlet and outlet cooling oil headers 28, 30. Theheaders are connected by inlet and outlet passages 32, 34 with an oilcooler connector 36, FIG. 3, in which the passages 32, 34 terminate atinlet and outlet ends 38, 40 extending to a generally flat oil coolerseal face 42.

The oil cooler connector is fastened, as by bolts 44, in opposed facerelation with a similar seal face 46, FIG. 4, of a mechanism/engineconnector 48 provided on the side 22 of the cylinder block or crankcase14 of the associated mechanism or engine 12. The mechanism/engine sealface 46 communicates with an outlet end 50 of an oil supply passage 52connecting internally with the engine oil pump, not shown. The seal face46 also communicates with the inlet end 54 of a return oil passage 56connecting internally with the mechanism/engine oil system 10 fordelivering the cooled oil to the lubrication system.

In order to provide a cooling fluid for the oil cooler 18, the oilcooler core 24 includes coolant passages 58, or an equivalent volume,with which the oil passages are in heat exchange relation within the oilcooler core 24. The passages 58 or volume may have any suitable flowpath through the core, such as a return flow path from a coolant inletheader 60 to a return flow header 62 and back to a coolant outlet header64. Inlet and outlet connections 66, 68 connect the headers 60, 64 withthe engine cooling system, not shown, to provide engine coolant to thecooler core passages (volume) 58.

If the oil cooler is connected to a transmission or other lubricatedmechanism, coolant may be supplied by an associated engine coolingsystem, or another source of coolant or cooling fluid may be provided.Any suitable coolant may be used including antifreeze containing liquidcoolants, as well as air or other suitable gaseous fluids if desired.

In accordance with the invention, a simplified oil bypass passage isprovided between the engine 12 and the oil cooler core 24. The passagereplaces a higher cost pressure actuated bypass valve of a prior systemand avoids the addition of an orifice, which would involve additionalcosts. Preferably, as shown in FIG. 3, the bypass passage is formed inthe oil cooler connector 36 and takes the form of a slot 70 of generallyrectangular open sided cross section. The slot 70 preferably extendsdirectly between the inlet and outlet ends 38, 40 of the cooler inletand outlet oil passages 32, 34. The slot is easily machined, as by anend mill, into the seal face 42 of the oil cooler connector with theslot open side 71 facing out from the seal face 42 toward the positionof the engine connector 46, when assembled with an engine, as shown inFIG. 1 of the drawings.

It should be understood that other forms of open sided grooves or slots(such as V-shaped, or U-shaped or forming a curved passage in the sealface, could be substituted for the preferred, straight slot withrectangular cross section configuration.

FIG. 4 shows another alternative embodiment of the invention wherein thebypass passage, or slot 72 with its open side 73, is formed in the sealface 46 of the engine connector 48. The configuration is shown as amirror image of the arrangement of FIG. 3 in that the seal face 46 ofthe engine connector 48, the outlet and inlet ends 50, 54 of the oilsupply passage 52 and the return oil passage 56, respectively, as wellas the slot 72 are similar to the comparable features of FIG. 3 exceptthat the oil supply passage 52 and the return oil passage 56 and theiroutlet and inlet ends 50, 54 are positioned on opposite ends of theirseal face 46 from the outlet and inlet ends 38, 40 of the oil coolerconnector of FIG. 3 with which they connect in assembly. The FIG. 4embodiment should give equivalent bypass flow to that of FIG. 3, if thedimensions are equal, but the embodiment of FIG. 3 is consideredpreferable because the smaller oil cooler is perceived as being easierto handle for machining of the associated connector than that of thelarger engine block or crankcase.

Assembly of the oil cooler onto the engine requires only the addition ofa “perimeter seal” gasket 74, shown in FIG. 5 in position on the oilcooler connector 36. The gasket 74 is clamped between the seal faces 42,46 of the oil cooler connector 36 and the engine connector 48 as the oilcooler 18 is mounted on the engine 12.

The gasket 74, FIG. 5, includes a racetrack shaped central opening 76,which has semicircular edges 78 that border the outer perimeters of thepassage ends, which terminate in both the engine and oil coolerconnectors 48, 36. The opening 76 also has connecting straight edges 80that join tangentially with opposite ends of the semicircular edges 78.The opening thereby surrounds the oil passage ends 38, 40, terminatingin both the oil cooler and engine connectors as well as the volumebetween the seal faces 46, 42 within the opening 76 between the passageends. This volume includes the volume of the associated bypass slot 70in the oil cooler connector or the alternative bypass slot 72 in theengine connector. Use of the perimeter seal gasket is more economicalthan a previous edge bonded rubber gasket which separately sealed theinlet and outlet passages from bypassing the oil cooler flow.

FIG. 6 illustrates the configuration and total cross-sectional area 82of an exemplary oil cooler bypass opening formed between and within theseal faces 46, 42 of the engine and oil cooler connectors 48, 36. Theshorter and thicker rectangle 84 illustrates the cross-sectional bypassflow area of the slot 70 in the seal face 42 of the oil cooler connector36. The thinner and longer rectangle 86 illustrates the cross-sectionalarea of the volume formed between the engine and oil cooler connectorseal faces 46, 42 which equals the thickness of the perimeter gasketwithin the width of the gasket opening 76. The total of the tworectangles 84, 86 equals the flow area of the bypass passage for oilflow bypassing the oil cooler core when the associated engine is inoperation and providing a continuous oil flow to the bearings and otherlubricated parts of the engine, even though there is excessive oilviscosity or the cooler core becomes clogged by contaminants thatprevent adequate oil flow through the oil cooler core.

It is apparent that the present invention provides a simple buteffective oil bypass for an oil cooler, which provides continuous oilbypass flow to protect the lubricated components of an engine ormechanism from damage due to oil starvation in spite of high oilviscosity or plugging of the oil passages of an associated oil cooler.The bypass arrangement is easily formed in a junction of inlet andoutlet oil passages in a connector in which a bypass groove or slot maybe machined or formed between the passages.

While the invention has been described by reference to certain preferredembodiments, it should be understood that numerous changes could be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedisclosed embodiments, but that it have the full scope permitted by thelanguage of the following claims.

1. A lubrication system for a lubricated mechanism, the systemcomprising: an oil cooler including a plurality of cooling oil passagesdisposed in heat exchange relation with internal coolant passages, thecooling oil passages terminating in spaced adjacent inlet and outletends opening through a seal face of an oil cooler connector; alubricated mechanism having oil supply and oil return passagesterminating in spaced adjacent outlet and inlet ends opening through aseal face of a mechanism connector disposed in opposed face relationwith the oil cooler connector, with the outlet end of the mechanism oilsupply passage connected with the inlet end of the oil cooler passagesand the outlet end of the oil cooler passages connected with the inletend of the mechanism oil return passage; and a bypass groove extendingin the seal face of at least one of the oil cooler connector and themechanism connector, the groove extending between the inlet and outletends of the passages associated with the at least one connector forcarrying oil through the groove to bypass the oil cooler passages.
 2. Alubrication system as in claim 1 wherein the bypass groove is in the oilcooler connector.
 3. A lubrication system as in claim 1 wherein thebypass groove is in the mechanism connector.
 4. A lubrication system asin claim 1 wherein the groove is a slot of generally rectangular opensided cross section extending directly between the inlet and outlet endsof passages terminating in an associated connector.
 5. A lubricationsystem as in claim 4 including a peripheral gasket disposed between andengaging the seal faces of the oil cooler connector and the mechanismconnector and forming a sealed joint surrounding the slot and the inletand outlet ends of the passages terminating in the connectors.
 6. An oilcooler for use in cooling oil used in operation of a lubricatedmechanism, the oil cooler comprising: a core including a plurality ofcore oil passages extending through the core between and connecting withinlet and outlet headers, the core including coolant passages disposedin heat exchange relation with the core oil passages; oil inlet andoutlet passages connected respectively with the inlet and outlet headersand terminating in spaced adjacent inlet and outlet ends opening througha seal face of a connector attachable to a source of inlet oilconnectable with the inlet end and a cooled oil receiver attachable withthe outlet end; the connector including a bypass groove extending in theseal face between the inlet and outlet ends for carrying oil through thegroove to bypass the core oil passages.
 7. An oil cooler as in claim 6wherein the groove is a slot of generally rectangular open sided crosssection extending directly between the inlet and outlet ends of passagesterminating in the connector.
 8. An oil cooler as in claim 6 including aperipheral gasket disposed between and engaging the seal face of the oilcooler connector and adapted to form a sealed joint with an associatedmechanism connector surrounding the slot and the inlet and outlet endsof the passages terminating in the connector.